Conventionally, the following method for manufacturing a multilayer wiring board is employed. A prepreg or a resin film and metal foils on both sides of the prepreg or the resin film are integrally laminated. A hole for via-hole is disposed by drilling or laser. A base electroless plating layer is formed. Afterwards, the hole for via-hole is plugged up with an electrolytic plating layer (hereinafter may be simply referred to as an “electrolytic filled plating layer”) formed using an electrolytic filled via plating solution.
Recently, the following method for manufacturing a multilayer wiring board is also employed (Patent Literatures 1 and 2). A base electroless plating layer is formed. Afterwards, a via-hole (hereinafter may be simply referred to as a “through-hole”) having a via-diameter smaller than an insulating layer thickness and passing through an insulating material integrally laminated with metal foils is plugged up using an electrolytic filled via plating solution.